Answer : Let A denote the event that a person will get electrification contract and B denote the event that the person will get a plumbing contract

Given : P(A) =  2/5  , P(not B) =4/5   , P(A or B) =2/3

To find: Probability that he will get both electrification and plumbing contract = P(A and B)

Formula used : P(B) = 1 – P() P(A or B) = P(A) + P(B) – P(A and B)

P(B) = 1 -3/7

P(B) = 3/7

Probability of getting at least one contract

P(A and B) = 17/105

P(A and B) = 17/105

The probability that he will get both electrification and plumbing contract = 17/105